diff mbox series

[04/15] PCI: Add pci_find_vsec_capability() to find a specific VSEC

Message ID cc4b62f333342df8e029b175079203cfe2bd095c.1608053262.git.gustavo.pimentel@synopsys.com
State New
Headers show
Series dmaengine: dw-edma: HDMA support | expand

Commit Message

Gustavo Pimentel Dec. 15, 2020, 5:30 p.m. UTC
Add pci_find_vsec_capability() that crawls through the device config
space searching in all Vendor-Specific Extended Capabilities for a
particular capability ID.

Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts
like a wrapper) specified by PCI-SIG that allows the vendor to create
their own and specific capability in the device config space.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
---
 drivers/pci/pci.c             | 29 +++++++++++++++++++++++++++++
 include/linux/pci.h           |  1 +
 include/uapi/linux/pci_regs.h |  5 +++++
 3 files changed, 35 insertions(+)

Comments

Bjorn Helgaas Feb. 1, 2021, 10:39 p.m. UTC | #1
[+cc Vinod, Dan, dmaengine]

On Tue, Dec 15, 2020 at 06:30:13PM +0100, Gustavo Pimentel wrote:
> Add pci_find_vsec_capability() that crawls through the device config
> space searching in all Vendor-Specific Extended Capabilities for a
> particular capability ID.
> 
> Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts
> like a wrapper) specified by PCI-SIG that allows the vendor to create
> their own and specific capability in the device config space.
> 
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

If you fix the below, feel free to add my

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Otherwise, I can take it myself.  But that will be an ordering issue
in the merge window if you merge the rest of the series via another
tree.

> ---
>  drivers/pci/pci.c             | 29 +++++++++++++++++++++++++++++
>  include/linux/pci.h           |  1 +
>  include/uapi/linux/pci_regs.h |  5 +++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 6d4d5a2..235d0b2 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -623,6 +623,35 @@ u64 pci_get_dsn(struct pci_dev *dev)
>  }
>  EXPORT_SYMBOL_GPL(pci_get_dsn);
>  
> +/**
> + * pci_find_vsec_capability - Find a vendor-specific extended capability
> + * @dev: PCI device to query
> + * @cap: vendor-specific capability id code

s/id/ID/

> + *
> + * Returns the address of the vendor-specific structure that matches the
> + * requested capability id code within the device's PCI configuration space

s/id/ID/

> + * or 0 if it does not find a match.
> + */
> +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id)
> +{
> +	u32 header;
> +	int vsec;

  int vsec;
  u32 header;

since that's the order they're used.

> +
> +	vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR);
> +	while (vsec) {
> +		if (pci_read_config_dword(dev, vsec + 0x4,

s/0x4/PCI_VSEC_HDR/

> +					  &header) == PCIBIOS_SUCCESSFUL &&
> +		    PCI_VSEC_CAP_ID(header) == vsec_cap_id)
> +			break;

  return vsec;

> +
> +		vsec = pci_find_next_ext_capability(dev, vsec,
> +						    PCI_EXT_CAP_ID_VNDR);
> +	}
> +
> +	return vsec;

  return 0;

> +}
> +EXPORT_SYMBOL_GPL(pci_find_vsec_capability);
> +
>  static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
>  {
>  	int rc, ttl = PCI_FIND_CAP_TTL;
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 22207a7..effecb0 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1067,6 +1067,7 @@ int pci_find_capability(struct pci_dev *dev, int cap);
>  int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
>  int pci_find_ext_capability(struct pci_dev *dev, int cap);
>  int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap);
> +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id);
>  int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
>  int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
>  struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index a95d55f..f5d17be 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -730,6 +730,11 @@
>  #define PCI_EXT_CAP_DSN_SIZEOF	12
>  #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
>  
> +/* Vendor-Specific Extended Capabilities */
> +#define PCI_VSEC_CAP_ID(header)		(header & 0x0000ffff)
> +#define PCI_VSEC_CAP_REV(header)	((header >> 16) & 0xf)
> +#define PCI_VSEC_CAP_LEN(header)	((header >> 20) & 0xffc)

Please put these next to the existing PCI_VSEC_HDR.

Why does PCI_VSEC_CAP_LEN mask with 0xffc instead of 0xfff?  I don't
see anything in the spec about VSEC Length having to be a multiple of
4 (PCIe r5.0, sec 7.9.5.2).

But you don't use this anyway, so I'd just drop it (and
PCI_VSEC_CAP_REV) altogether.

>  /* Advanced Error Reporting */
>  #define PCI_ERR_UNCOR_STATUS	4	/* Uncorrectable Error Status */
>  #define  PCI_ERR_UNC_UND	0x00000001	/* Undefined */
> -- 
> 2.7.4
>
Dan Williams Feb. 1, 2021, 11:24 p.m. UTC | #2
[ add Ben ]

On Mon, Feb 1, 2021 at 2:39 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> [+cc Vinod, Dan, dmaengine]
>
> On Tue, Dec 15, 2020 at 06:30:13PM +0100, Gustavo Pimentel wrote:
> > Add pci_find_vsec_capability() that crawls through the device config
> > space searching in all Vendor-Specific Extended Capabilities for a
> > particular capability ID.
> >
> > Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts
> > like a wrapper) specified by PCI-SIG that allows the vendor to create
> > their own and specific capability in the device config space.
> >
> > Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>
> If you fix the below, feel free to add my
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
> Otherwise, I can take it myself.  But that will be an ordering issue
> in the merge window if you merge the rest of the series via another
> tree.

I wonder if this warrants and if you'd be willing to stand up a stable
branch for just this commit for concerned parties to integrate,
because CXL development should adopt it as well.

>
> > ---
> >  drivers/pci/pci.c             | 29 +++++++++++++++++++++++++++++
> >  include/linux/pci.h           |  1 +
> >  include/uapi/linux/pci_regs.h |  5 +++++
> >  3 files changed, 35 insertions(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 6d4d5a2..235d0b2 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -623,6 +623,35 @@ u64 pci_get_dsn(struct pci_dev *dev)
> >  }
> >  EXPORT_SYMBOL_GPL(pci_get_dsn);
> >
> > +/**
> > + * pci_find_vsec_capability - Find a vendor-specific extended capability
> > + * @dev: PCI device to query
> > + * @cap: vendor-specific capability id code
>
> s/id/ID/
>
> > + *
> > + * Returns the address of the vendor-specific structure that matches the
> > + * requested capability id code within the device's PCI configuration space
>
> s/id/ID/
>
> > + * or 0 if it does not find a match.
> > + */
> > +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id)
> > +{
> > +     u32 header;
> > +     int vsec;
>
>   int vsec;
>   u32 header;
>
> since that's the order they're used.
>
> > +
> > +     vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR);
> > +     while (vsec) {
> > +             if (pci_read_config_dword(dev, vsec + 0x4,
>
> s/0x4/PCI_VSEC_HDR/
>
> > +                                       &header) == PCIBIOS_SUCCESSFUL &&
> > +                 PCI_VSEC_CAP_ID(header) == vsec_cap_id)
> > +                     break;
>
>   return vsec;
>
> > +
> > +             vsec = pci_find_next_ext_capability(dev, vsec,
> > +                                                 PCI_EXT_CAP_ID_VNDR);
> > +     }
> > +
> > +     return vsec;
>
>   return 0;
>
> > +}
> > +EXPORT_SYMBOL_GPL(pci_find_vsec_capability);
> > +
> >  static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
> >  {
> >       int rc, ttl = PCI_FIND_CAP_TTL;
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 22207a7..effecb0 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -1067,6 +1067,7 @@ int pci_find_capability(struct pci_dev *dev, int cap);
> >  int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
> >  int pci_find_ext_capability(struct pci_dev *dev, int cap);
> >  int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap);
> > +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id);
> >  int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
> >  int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
> >  struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
> > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> > index a95d55f..f5d17be 100644
> > --- a/include/uapi/linux/pci_regs.h
> > +++ b/include/uapi/linux/pci_regs.h
> > @@ -730,6 +730,11 @@
> >  #define PCI_EXT_CAP_DSN_SIZEOF       12
> >  #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
> >
> > +/* Vendor-Specific Extended Capabilities */
> > +#define PCI_VSEC_CAP_ID(header)              (header & 0x0000ffff)
> > +#define PCI_VSEC_CAP_REV(header)     ((header >> 16) & 0xf)
> > +#define PCI_VSEC_CAP_LEN(header)     ((header >> 20) & 0xffc)
>
> Please put these next to the existing PCI_VSEC_HDR.
>
> Why does PCI_VSEC_CAP_LEN mask with 0xffc instead of 0xfff?  I don't
> see anything in the spec about VSEC Length having to be a multiple of
> 4 (PCIe r5.0, sec 7.9.5.2).
>
> But you don't use this anyway, so I'd just drop it (and
> PCI_VSEC_CAP_REV) altogether.
>
> >  /* Advanced Error Reporting */
> >  #define PCI_ERR_UNCOR_STATUS 4       /* Uncorrectable Error Status */
> >  #define  PCI_ERR_UNC_UND     0x00000001      /* Undefined */
> > --
> > 2.7.4
> >
Ben Widawsky Feb. 1, 2021, 11:29 p.m. UTC | #3
On 21-02-01 15:24:45, Dan Williams wrote:
> [ add Ben ]
> 
> On Mon, Feb 1, 2021 at 2:39 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >
> > [+cc Vinod, Dan, dmaengine]
> >
> > On Tue, Dec 15, 2020 at 06:30:13PM +0100, Gustavo Pimentel wrote:
> > > Add pci_find_vsec_capability() that crawls through the device config
> > > space searching in all Vendor-Specific Extended Capabilities for a
> > > particular capability ID.
> > >
> > > Vendor-Specific Extended Capability (VSEC) is a PCIe capability (acts
> > > like a wrapper) specified by PCI-SIG that allows the vendor to create
> > > their own and specific capability in the device config space.
> > >
> > > Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> >
> > If you fix the below, feel free to add my
> >
> > Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> >
> > Otherwise, I can take it myself.  But that will be an ordering issue
> > in the merge window if you merge the rest of the series via another
> > tree.
> 
> I wonder if this warrants and if you'd be willing to stand up a stable
> branch for just this commit for concerned parties to integrate,
> because CXL development should adopt it as well.
> 

Yeah, can we add DVSEC too please?

> >
> > > ---
> > >  drivers/pci/pci.c             | 29 +++++++++++++++++++++++++++++
> > >  include/linux/pci.h           |  1 +
> > >  include/uapi/linux/pci_regs.h |  5 +++++
> > >  3 files changed, 35 insertions(+)
> > >
> > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > > index 6d4d5a2..235d0b2 100644
> > > --- a/drivers/pci/pci.c
> > > +++ b/drivers/pci/pci.c
> > > @@ -623,6 +623,35 @@ u64 pci_get_dsn(struct pci_dev *dev)
> > >  }
> > >  EXPORT_SYMBOL_GPL(pci_get_dsn);
> > >
> > > +/**
> > > + * pci_find_vsec_capability - Find a vendor-specific extended capability
> > > + * @dev: PCI device to query
> > > + * @cap: vendor-specific capability id code
> >
> > s/id/ID/
> >
> > > + *
> > > + * Returns the address of the vendor-specific structure that matches the
> > > + * requested capability id code within the device's PCI configuration space
> >
> > s/id/ID/
> >
> > > + * or 0 if it does not find a match.
> > > + */
> > > +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id)
> > > +{
> > > +     u32 header;
> > > +     int vsec;
> >
> >   int vsec;
> >   u32 header;
> >
> > since that's the order they're used.
> >
> > > +
> > > +     vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR);
> > > +     while (vsec) {
> > > +             if (pci_read_config_dword(dev, vsec + 0x4,
> >
> > s/0x4/PCI_VSEC_HDR/
> >
> > > +                                       &header) == PCIBIOS_SUCCESSFUL &&
> > > +                 PCI_VSEC_CAP_ID(header) == vsec_cap_id)
> > > +                     break;
> >
> >   return vsec;
> >
> > > +
> > > +             vsec = pci_find_next_ext_capability(dev, vsec,
> > > +                                                 PCI_EXT_CAP_ID_VNDR);
> > > +     }
> > > +
> > > +     return vsec;
> >
> >   return 0;
> >
> > > +}
> > > +EXPORT_SYMBOL_GPL(pci_find_vsec_capability);
> > > +
> > >  static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
> > >  {
> > >       int rc, ttl = PCI_FIND_CAP_TTL;
> > > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > > index 22207a7..effecb0 100644
> > > --- a/include/linux/pci.h
> > > +++ b/include/linux/pci.h
> > > @@ -1067,6 +1067,7 @@ int pci_find_capability(struct pci_dev *dev, int cap);
> > >  int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
> > >  int pci_find_ext_capability(struct pci_dev *dev, int cap);
> > >  int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap);
> > > +int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id);
> > >  int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
> > >  int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
> > >  struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
> > > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> > > index a95d55f..f5d17be 100644
> > > --- a/include/uapi/linux/pci_regs.h
> > > +++ b/include/uapi/linux/pci_regs.h
> > > @@ -730,6 +730,11 @@
> > >  #define PCI_EXT_CAP_DSN_SIZEOF       12
> > >  #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
> > >
> > > +/* Vendor-Specific Extended Capabilities */
> > > +#define PCI_VSEC_CAP_ID(header)              (header & 0x0000ffff)
> > > +#define PCI_VSEC_CAP_REV(header)     ((header >> 16) & 0xf)
> > > +#define PCI_VSEC_CAP_LEN(header)     ((header >> 20) & 0xffc)
> >
> > Please put these next to the existing PCI_VSEC_HDR.
> >
> > Why does PCI_VSEC_CAP_LEN mask with 0xffc instead of 0xfff?  I don't
> > see anything in the spec about VSEC Length having to be a multiple of
> > 4 (PCIe r5.0, sec 7.9.5.2).
> >
> > But you don't use this anyway, so I'd just drop it (and
> > PCI_VSEC_CAP_REV) altogether.
> >
> > >  /* Advanced Error Reporting */
> > >  #define PCI_ERR_UNCOR_STATUS 4       /* Uncorrectable Error Status */
> > >  #define  PCI_ERR_UNC_UND     0x00000001      /* Undefined */
> > > --
> > > 2.7.4
> > >
Gustavo Pimentel Feb. 2, 2021, 12:25 p.m. UTC | #4
On Mon, Feb 1, 2021 at 22:39:20, Bjorn Helgaas <helgaas@kernel.org> 
wrote:

Hi Bjorn,

> > +/**
> > + * pci_find_vsec_capability - Find a vendor-specific extended capability
> > + * @dev: PCI device to query
> > + * @cap: vendor-specific capability id code
> 
> s/id/ID/

I will do it for all the requested changes.

> >  
> > +/* Vendor-Specific Extended Capabilities */
> > +#define PCI_VSEC_CAP_ID(header)		(header & 0x0000ffff)
> > +#define PCI_VSEC_CAP_REV(header)	((header >> 16) & 0xf)
> > +#define PCI_VSEC_CAP_LEN(header)	((header >> 20) & 0xffc)
> 
> Please put these next to the existing PCI_VSEC_HDR.

I will move it next to HDR. The 0xffc was a typo, thanks for noticing it.
About the PCI_VSEC_CAP_REV and PCI_VSEC_CAP_LEN macros, I will be using 
on dw_edma_pcie_get_vsec_dma_data() from dw-edma-pcie.c has a validation 
of the right DVSEC.

I will send a version 2 with those fixes.

-Gustavo
diff mbox series

Patch

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6d4d5a2..235d0b2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -623,6 +623,35 @@  u64 pci_get_dsn(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_get_dsn);
 
+/**
+ * pci_find_vsec_capability - Find a vendor-specific extended capability
+ * @dev: PCI device to query
+ * @cap: vendor-specific capability id code
+ *
+ * Returns the address of the vendor-specific structure that matches the
+ * requested capability id code within the device's PCI configuration space
+ * or 0 if it does not find a match.
+ */
+int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id)
+{
+	u32 header;
+	int vsec;
+
+	vsec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VNDR);
+	while (vsec) {
+		if (pci_read_config_dword(dev, vsec + 0x4,
+					  &header) == PCIBIOS_SUCCESSFUL &&
+		    PCI_VSEC_CAP_ID(header) == vsec_cap_id)
+			break;
+
+		vsec = pci_find_next_ext_capability(dev, vsec,
+						    PCI_EXT_CAP_ID_VNDR);
+	}
+
+	return vsec;
+}
+EXPORT_SYMBOL_GPL(pci_find_vsec_capability);
+
 static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
 {
 	int rc, ttl = PCI_FIND_CAP_TTL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a7..effecb0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1067,6 +1067,7 @@  int pci_find_capability(struct pci_dev *dev, int cap);
 int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
 int pci_find_ext_capability(struct pci_dev *dev, int cap);
 int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap);
+int pci_find_vsec_capability(struct pci_dev *dev, int vsec_cap_id);
 int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
 int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
 struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index a95d55f..f5d17be 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -730,6 +730,11 @@ 
 #define PCI_EXT_CAP_DSN_SIZEOF	12
 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
 
+/* Vendor-Specific Extended Capabilities */
+#define PCI_VSEC_CAP_ID(header)		(header & 0x0000ffff)
+#define PCI_VSEC_CAP_REV(header)	((header >> 16) & 0xf)
+#define PCI_VSEC_CAP_LEN(header)	((header >> 20) & 0xffc)
+
 /* Advanced Error Reporting */
 #define PCI_ERR_UNCOR_STATUS	4	/* Uncorrectable Error Status */
 #define  PCI_ERR_UNC_UND	0x00000001	/* Undefined */